Many titanium alloy subcomponents are subjected to fatigue loading in aerospace engineering,resulting in fatigue failure.The fatigue behavior of Ti_(2)AlNb alloy subcomponents was investigated based on the Seeger fati...Many titanium alloy subcomponents are subjected to fatigue loading in aerospace engineering,resulting in fatigue failure.The fatigue behavior of Ti_(2)AlNb alloy subcomponents was investigated based on the Seeger fatigue life theory and the improved Lemaitre damage evolution theory.Firstly,the finite element models of the standard openhole specimen and Y-section subcomponents have been established by ABAQUS.The damage model parameters were determined by fatigue tests,and the reliability of fatigue life simulation results of the Ti_(2)AlNb alloy standard open-hole specimen was verified.Meanwhile,the fatigue life of Ti_(2)AlNb alloy Y-section subcomponents was predicted.Under the same initial conditions,the average error of fatigue life predicted by two different models was 20.6%.Finally,the effects of loading amplitude,temperature,and Y-interface angle on fatigue properties of Ti_(2)AlNb Y-section subcomponents were investigated.These results provide a new idea for evaluating the fatigue life of various Ti_(2)AlNb alloy subcomponents.展开更多
Ti2AlNb-based alloys with 0.0 wt%, 0.6 wt%, and 2.0 wt% carbon nanotube(CNT) addition were fabricated from spherical Ti–22 Al–25 Nb powder by sintering in the B2 single-phase region. Phase identification and micro...Ti2AlNb-based alloys with 0.0 wt%, 0.6 wt%, and 2.0 wt% carbon nanotube(CNT) addition were fabricated from spherical Ti–22 Al–25 Nb powder by sintering in the B2 single-phase region. Phase identification and microstructural examination were performed to evaluate the effect of carbon addition on the hardness of the alloys. Carbon was either in a soluble state or in carbide form depending on its concentration. The acicular carbides formed around 1050℃ were identified as TiC and facilitated the transformation of α2 + B2 → O. The TiC was located within the acicular O phase. The surrounding O phase was distributed in certain orientations with angles of 65° or 90° O phase particles. The obtained alloy was composed of acicular O, Widmanstatten B2 +O, and acicular TiC. As a result of the precipitation of carbides as well as the O phase, the hardness of the alloy with 2.0 wt% CNT addition increased to HV 429 ± 9.展开更多
The effect of yttrium on the oxidation resistance of as-cast Ti2AlNb based alloy was studied.With the addition of Y,the oxidation resistance of the experimental alloys was improved at 700-850 ℃.The improvement of the...The effect of yttrium on the oxidation resistance of as-cast Ti2AlNb based alloy was studied.With the addition of Y,the oxidation resistance of the experimental alloys was improved at 700-850 ℃.The improvement of the oxidation resistance was attributed to the refinement of the oxide scale and the appearance of transition layer.展开更多
The microstructure and hot tensile behaviors of the different heat-treated Ti2AlNb sheets were investigated by backscattered electron image(BSE),electron backscattering diffraction(EBSD),transmission electron microsco...The microstructure and hot tensile behaviors of the different heat-treated Ti2AlNb sheets were investigated by backscattered electron image(BSE),electron backscattering diffraction(EBSD),transmission electron microscope(TEM)and tensile tests.The grain sizes and contents ofα2,B2/βand O phases were quantitatively studied.As the heating time increases at 970℃,the mean grain size and content ofα2-phase increased.The grain shapes and distributions of the O-phase lamellar grains were affected by the heat treatments.The plastic deformation promoted the O→B2/βphase transition and the globularization of O-phase lamellar grains at 970℃.Calculated by the creep equation and the iso-stress method,the grain size exponent wasμ=1.1 and the relationship between the material constants of B2/βand O phase was KO=1.14KB2/β.展开更多
基金the financial support provided by the National Science and TechnologyMajor Project(No.J2019-VI-0003-0116)the Six Talent Peaks Project in Jiangsu Province(Grant No.2019-KTHY-059).
文摘Many titanium alloy subcomponents are subjected to fatigue loading in aerospace engineering,resulting in fatigue failure.The fatigue behavior of Ti_(2)AlNb alloy subcomponents was investigated based on the Seeger fatigue life theory and the improved Lemaitre damage evolution theory.Firstly,the finite element models of the standard openhole specimen and Y-section subcomponents have been established by ABAQUS.The damage model parameters were determined by fatigue tests,and the reliability of fatigue life simulation results of the Ti_(2)AlNb alloy standard open-hole specimen was verified.Meanwhile,the fatigue life of Ti_(2)AlNb alloy Y-section subcomponents was predicted.Under the same initial conditions,the average error of fatigue life predicted by two different models was 20.6%.Finally,the effects of loading amplitude,temperature,and Y-interface angle on fatigue properties of Ti_(2)AlNb Y-section subcomponents were investigated.These results provide a new idea for evaluating the fatigue life of various Ti_(2)AlNb alloy subcomponents.
基金the China National Funds for Distinguished Young Scientists (No. 51325401)the National Natural Science Foundation of China (Nos. 51474156 and U1660201)the National Magnetic Confinement Fusion Energy Research Program of China (No. 2014GB125006) for financial support
文摘Ti2AlNb-based alloys with 0.0 wt%, 0.6 wt%, and 2.0 wt% carbon nanotube(CNT) addition were fabricated from spherical Ti–22 Al–25 Nb powder by sintering in the B2 single-phase region. Phase identification and microstructural examination were performed to evaluate the effect of carbon addition on the hardness of the alloys. Carbon was either in a soluble state or in carbide form depending on its concentration. The acicular carbides formed around 1050℃ were identified as TiC and facilitated the transformation of α2 + B2 → O. The TiC was located within the acicular O phase. The surrounding O phase was distributed in certain orientations with angles of 65° or 90° O phase particles. The obtained alloy was composed of acicular O, Widmanstatten B2 +O, and acicular TiC. As a result of the precipitation of carbides as well as the O phase, the hardness of the alloy with 2.0 wt% CNT addition increased to HV 429 ± 9.
文摘The effect of yttrium on the oxidation resistance of as-cast Ti2AlNb based alloy was studied.With the addition of Y,the oxidation resistance of the experimental alloys was improved at 700-850 ℃.The improvement of the oxidation resistance was attributed to the refinement of the oxide scale and the appearance of transition layer.
基金financially supported the National Natural Science Foundation of China(No.51805256)。
文摘The microstructure and hot tensile behaviors of the different heat-treated Ti2AlNb sheets were investigated by backscattered electron image(BSE),electron backscattering diffraction(EBSD),transmission electron microscope(TEM)and tensile tests.The grain sizes and contents ofα2,B2/βand O phases were quantitatively studied.As the heating time increases at 970℃,the mean grain size and content ofα2-phase increased.The grain shapes and distributions of the O-phase lamellar grains were affected by the heat treatments.The plastic deformation promoted the O→B2/βphase transition and the globularization of O-phase lamellar grains at 970℃.Calculated by the creep equation and the iso-stress method,the grain size exponent wasμ=1.1 and the relationship between the material constants of B2/βand O phase was KO=1.14KB2/β.